Antenna Modulation Method for Massive MIMO Systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Massive MIMO antenna systems face challenges in achieving accurate channel state information (CSI) for effective beamforming, particularly in frequency-division duplex systems, and existing spatial domain modulation schemes like Spatial Modulation (SM) and Generalized Space Shift Keying (GSSK) face limitations in noisy channels and high computational complexity.
Innovation Solution
An antenna modulation method that converts a bit stream into coordinate points of a signal constellation, generating vectors that map to specific antennas, allowing for activation based on non-zero entries, thereby eliminating the need for accurate CSI and reducing computational complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If massive MIMO antenna techniques are used to achieve high beamforming gains, then link gains are improved, but accurate channel state information (CSI) is required which is difficult to acquire in FDD systems
Solution Approach 1:
The invention extracts the CSI requirement from the beamforming process by using spatial domain modulation. Instead of relying on accurate CSI for beamforming, the system uses antenna selection and spatial multiplexing that do not require channel knowledge at the transmitter, thereby eliminating the complexity of CSI acquisition while maintaining link gains through spatial diversity.
Solution Approach 2:
The invention replaces the mechanical system of CSI measurement and feedback with a mathematical transformation approach. By using singular value decomposition (SVD) and spatial domain modulation, the system achieves beamforming-like performance through signal processing rather than physical channel measurement, eliminating the need for complex CSI acquisition infrastructure.
2Productivity
If higher-order modulation schemes are used to boost data rates in SM and GSSK, then data rates are improved, but performance degrades in noisy channels
Solution Approach 1:
The invention moves the modulation from the amplitude-phase domain (higher-order QAM) to the spatial domain (antenna selection and activation). By encoding information in the spatial dimension through antenna indexing and activation patterns, the system achieves high data rates without increasing modulation order, thereby maintaining robustness in noisy channels while improving productivity.
3Measurement precision
If maximum-likelihood (ML) detection is used for SM and GSSK to achieve optimal performance, then detection accuracy is improved, but computational complexity becomes unacceptable
Solution Approach 1:
The invention segments the detection process into two independent stages: spatial domain detection (antenna selection) and symbol detection. By separating the detection of spatial indices from the detection of modulation symbols, the system avoids the exponential complexity of ML detection while maintaining detection accuracy through iterative or sequential processing of the segmented components.
4Productivity
If the number of antennas is increased to achieve high data rates in SDM schemes, then data rates are improved, but hardware costs and energy consumption increase
Solution Approach 1:
The invention makes each antenna multi-functional by enabling dynamic activation and deactivation based on channel conditions and data rate requirements. Instead of continuously operating all antennas, the system selectively activates only the necessary number of antennas, allowing each antenna to serve multiple purposes (spatial multiplexing, diversity, and adaptive rate control) thereby reducing energy consumption while maintaining high data rates.
Data Source
Figure 1A~1B
Figure 2
Figure 3A
AI summary
An antenna modulation method applicable to a transmitter comprising a processing unit which is configured to execute functions including at least but not limited to receiving a symbol represented by a bit stream; converting the bit stream into a coordinate point of a signal constellation comprising a horizontal-axis component and a vertical-axis component; converting, from the horizontal-axis component of the coordinate point, a first vector having at least a first entry and a second entry; converting, from the vertical-axis component of the coordinate point, a second vector having at least a third entry and a fourth entry; generating a third vector having at least a fifth entry and a sixth entry by summing the first vector and the second vector; and activating at least one of the first antenna and the second antennas based on one or more non-zero entries of the third vector.